Resolve UI outlines using the correct target's viewport size (#14947)

`resolve_outlines_system` wasn't updated when multi-window support was
added and it always uses the size of the primary window when resolving
viewport coords, regardless of the layout's camera target.

Fixes #14945

It's awkward to get the viewport size of the target for an individual
node without walking the tree or adding extra fields to `Node`, so I
removed `resolve_outlines_system` and instead the outline values are
updated in `ui_layout_system`.

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>

crates/bevy_ui/src/accessibility.rs

@@ -154,7 +154,6 @@ impl Plugin for AccessibilityPlugin {
                     .after(bevy_transform::TransformSystem::TransformPropagate)
                     .after(CameraUpdateSystem)
                     // the listed systems do not affect calculated size
-                    .ambiguous_with(crate::resolve_outlines_system)
                     .ambiguous_with(crate::ui_stack_system),
                 button_changed,
                 image_changed,

crates/bevy_ui/src/layout/mod.rs

@@ -93,7 +93,7 @@ pub fn ui_layout_system(
     children_query: Query<(Entity, Ref<Children>), With<Node>>,
     just_children_query: Query<&Children>,
     mut removed_components: UiLayoutSystemRemovedComponentParam,
-    mut node_transform_query: Query<(&mut Node, &mut Transform)>,
+    mut node_transform_query: Query<(&mut Node, &mut Transform, Option<&Outline>)>,
 ) {
     struct CameraLayoutInfo {
         size: UVec2,
@@ -232,6 +232,7 @@ pub fn ui_layout_system(
             update_uinode_geometry_recursive(
                 *root,
                 &ui_surface,
+                None,
                 &mut node_transform_query,
                 &just_children_query,
                 inverse_target_scale_factor,
@@ -244,13 +245,14 @@ pub fn ui_layout_system(
     fn update_uinode_geometry_recursive(
         entity: Entity,
         ui_surface: &UiSurface,
-        node_transform_query: &mut Query<(&mut Node, &mut Transform)>,
+        root_size: Option<Vec2>,
+        node_transform_query: &mut Query<(&mut Node, &mut Transform, Option<&Outline>)>,
         children_query: &Query<&Children>,
         inverse_target_scale_factor: f32,
         parent_size: Vec2,
         mut absolute_location: Vec2,
     ) {
-        if let Ok((mut node, mut transform)) = node_transform_query.get_mut(entity) {
+        if let Ok((mut node, mut transform, outline)) = node_transform_query.get_mut(entity) {
             let Ok(layout) = ui_surface.get_layout(entity) else {
                 return;
             };
@@ -272,14 +274,35 @@ pub fn ui_layout_system(
                 node.calculated_size = rounded_size;
                 node.unrounded_size = layout_size;
             }
+
+            let viewport_size = root_size.unwrap_or(node.calculated_size);
+
+            if let Some(outline) = outline {
+                // don't trigger change detection when only outlines are changed
+                let node = node.bypass_change_detection();
+                node.outline_width = outline
+                    .width
+                    .resolve(node.size().x, viewport_size)
+                    .unwrap_or(0.)
+                    .max(0.);
+
+                node.outline_offset = outline
+                    .offset
+                    .resolve(node.size().x, viewport_size)
+                    .unwrap_or(0.)
+                    .max(0.);
+            }
+
             if transform.translation.truncate() != rounded_location {
                 transform.translation = rounded_location.extend(0.);
             }
+
             if let Ok(children) = children_query.get(entity) {
                 for &child_uinode in children {
                     update_uinode_geometry_recursive(
                         child_uinode,
                         ui_surface,
+                        Some(viewport_size),
                         node_transform_query,
                         children_query,
                         inverse_target_scale_factor,
@@ -292,34 +315,6 @@ pub fn ui_layout_system(
     }
 }
 
-/// Resolve and update the widths of Node outlines
-pub fn resolve_outlines_system(
-    primary_window: Query<&Window, With<PrimaryWindow>>,
-    ui_scale: Res<UiScale>,
-    mut outlines_query: Query<(&Outline, &mut Node)>,
-) {
-    let viewport_size = primary_window
-        .get_single()
-        .map(|window| window.size())
-        .unwrap_or(Vec2::ZERO)
-        / ui_scale.0;
-
-    for (outline, mut node) in outlines_query.iter_mut() {
-        let node = node.bypass_change_detection();
-        node.outline_width = outline
-            .width
-            .resolve(node.size().x, viewport_size)
-            .unwrap_or(0.)
-            .max(0.);
-
-        node.outline_offset = outline
-            .offset
-            .resolve(node.size().x, viewport_size)
-            .unwrap_or(0.)
-            .max(0.);
-    }
-}
-
 #[inline]
 /// Round `value` to the nearest whole integer, with ties (values with a fractional part equal to 0.5) rounded towards positive infinity.
 fn round_ties_up(value: f32) -> f32 {

crates/bevy_ui/src/lib.rs

@@ -77,8 +77,6 @@ pub enum UiSystem {
     Focus,
     /// After this label, the [`UiStack`] resource has been updated
     Stack,
-    /// After this label, node outline widths have been updated
-    Outlines,
 }
 
 /// The current scale of the UI.
@@ -132,13 +130,7 @@ impl Plugin for UiPlugin {
             .register_type::<Outline>()
             .configure_sets(
                 PostUpdate,
-                (
-                    CameraUpdateSystem,
-                    UiSystem::Stack,
-                    UiSystem::Layout,
-                    UiSystem::Outlines,
-                )
-                    .chain(),
+                (CameraUpdateSystem, UiSystem::Stack, UiSystem::Layout).chain(),
             )
             .add_systems(
                 PreUpdate,
@@ -156,17 +148,10 @@ impl Plugin for UiPlugin {
                 ui_layout_system
                     .in_set(UiSystem::Layout)
                     .before(TransformSystem::TransformPropagate),
-                resolve_outlines_system
-                    .in_set(UiSystem::Outlines)
-                    .after(UiSystem::Layout)
-                    // clipping doesn't care about outlines
-                    .ambiguous_with(update_clipping_system)
-                    .in_set(AmbiguousWithTextSystem),
                 ui_stack_system
                     .in_set(UiSystem::Stack)
                     // the systems don't care about stack index
                     .ambiguous_with(update_clipping_system)
-                    .ambiguous_with(resolve_outlines_system)
                     .ambiguous_with(ui_layout_system)
                     .in_set(AmbiguousWithTextSystem),
                 update_clipping_system.after(TransformSystem::TransformPropagate),

crates/bevy_ui/src/ui_node.rs

@@ -35,10 +35,14 @@ pub struct Node {
     pub(crate) calculated_size: Vec2,
     /// The width of this node's outline.
     /// If this value is `Auto`, negative or `0.` then no outline will be rendered.
+    /// Outline updates bypass change detection.
     ///
-    /// Automatically calculated by [`super::layout::resolve_outlines_system`].
+    /// Automatically calculated by [`super::layout::ui_layout_system`].
     pub(crate) outline_width: f32,
     /// The amount of space between the outline and the edge of the node.
+    /// Outline updates bypass change detection.
+    ///
+    /// Automatically calculated by [`super::layout::ui_layout_system`].
     pub(crate) outline_offset: f32,
     /// The unrounded size of the node as width and height in logical pixels.
     ///